Rimless eyeglasses, also known as drilled-lens glasses due to the holes formed through the thickness of the lenses for fastening the frame, are becoming more and more widespread.
Reference can be made in particular to the following documents: WO 2004/003632 A, WO 02/21193 A, EP 1 107 042 A, WO 96/05535 A, U.S. Pat. No. 6,447,517 A, U.S. Pat. No. 5,042,933, US 2003/0058401, WO 00/26716 A, EP 1 382 988 A, WO 03/014804 A, WO 02/095482 A, WO 02/095481 A, and WO 81/01749 A.
In the above-mentioned arrangements, two holes or else one hole and an open notch in the side, are provided for each element constituting the frame, i.e. the bridge and each of the side branches.
In most circumstances, the fastening ends of the side branches are of a configuration that is complex, with multiple bends, thus implying a fabrication cost that is high. Furthermore, it is sometimes necessary to perform such bending in situ, after threading an end of the branch through a hole in the lens while said end was still rectilinear and had yet to be bent, as shown in document US A 2004/0051843, which is particularly inconvenient for the operator.
Reference can also be made to document FR 2 723 649 A which describes a wire frame having tenons comprising two superposed branches passing through the lenses from front to back, by passing through associated holes. The ends of those branches that project rearwards from the lenses receive protective caps that are secured by adhesive.
More recently, the Applicant has proposed a frame arrangement in which the wire structure is very simple, thereby making it convenient and fast to assemble with the lenses, not requiring any special tooling, and likewise without the fastening of the frame on the lenses leading to any risk of the corresponding zone of the lenses being weakened, in particular as a result of excessive clamping, as described in document WO 2006/027428 A. The wire structure in question has single-wire side branches that are terminated by J-shaped distal ends, with a long portion passing through a through hole in the lens having a flexible clamping bushing interposed therein, and with a short anti-rotation portion turned rearwards and passing through an open notch in the side or through another hole in the lens, but without clamping the lens between said long portion and said short portion.